Ignore all schemas plugins.

Checklist

[x] I have read the contribution guidelines
[ ] Pull request provided for main branch, backports managed with label
[ ] Good housekeeping of code, cleaning up comments, tests, and documentation
[ ] Clean commit history broken into understandable chucks, avoiding big commits with hundreds of files, cautious of reformatting and whitespace changes
[ ] Clean commit messages, longer verbose messages are encouraged
[ ] API Changes are identified in commit messages
[ ] Testing provided for features or enhancements using automatic tests
[ ] User documentation provided for new features or enhancements in manual
[ ] Build documentation provided for development instructions in README.md files
[ ] Library management using pom.xml dependency management. Update build documentation with intended library use and library tutorials or documentation

geonetwork / core-geonetwork